Time
Time is not an afterthought; it is co-equal with position.
Every element of the model is temporally extended
- A field's spatial profile drifts as the work it represents shifts.
- A field's weight rises and falls as concerns gain and lose currency.
- A stream is constitutively temporal — there is no stream without time.
- A projection has a temporal lens: it can be taken at the present moment, at a prior moment, or integrated over a window.
- Resources have temporal validity — they are true with respect to a field configuration that may have since changed.
- Perspectives are themselves trajectories rather than points (perspectives returns to this).
Why this forces events as the substrate
Bidirectional coupling forces a substantive substrate commitment. If the manifold's geometry is a function of stream history, then stream history is the primary data and the manifold is derived. Event-sourcing is not one substrate option among many; it is the only substrate consistent with the model. Distributed, ledger-flavored, or single-node implementations all remain viable, but events-as-primary is load-bearing for the semantics. Geometry is computed against history rather than maintained as a separate snapshot.
Two consequences follow that the model commits to. First, entity-state is itself derivable from events — role-changes, position-updates, membership-changes are all emissions of state-change topics, append-only like everything else. The substrate doesn't store entity-state; it stores the events from which entity-state is computed. Second, point-in-time truth is cross-cutting: for any event at time T, the state of every entity associated with that event — emitter, on-behalf-of scopes, observers — is projectable at T from their trajectories. The substrate carries the events; everything else, including the temporal truth of who-was-where-when, is computed.
Specific implementations remain downstream of the model. Caching, indexing, and materialization tradeoffs — when derived structure must be maintained rather than computed, and what reconciliation looks like when it is — are open.